Revert "Input: serio - make write method mandatory"

This reverts commit 81c7c0a. The idea to make write method mandatory was flawed as several client drivers (such as atkbd) check for presence of write() method to adjust behavior of the driver. Reported-by: Nathan Chancellor <[email protected]> Reported-by: Michael Kelley <[email protected]> Signed-off-by: Dmitry Torokhov <[email protected]>
bignaux · Jul 21, 2021 · 7d3370e · 7d3370e
1 parent 133b655
commit 7d3370e
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Showing 3 changed files with 4 additions and 12 deletions.
diff --git a/drivers/input/serio/ams_delta_serio.c b/drivers/input/serio/ams_delta_serio.c
@@ -89,11 +89,6 @@ static irqreturn_t ams_delta_serio_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-static int ams_delta_serio_write(struct serio *serio, u8 data)
-{
-	return -EINVAL;
-}
-
 static int ams_delta_serio_open(struct serio *serio)
 {
 	struct ams_delta_serio *priv = serio->port_data;
@@ -162,7 +157,6 @@ static int ams_delta_serio_init(struct platform_device *pdev)
 	priv->serio = serio;
 
 	serio->id.type = SERIO_8042;
-	serio->write = ams_delta_serio_write;
 	serio->open = ams_delta_serio_open;
 	serio->close = ams_delta_serio_close;
 	strlcpy(serio->name, "AMS DELTA keyboard adapter", sizeof(serio->name));

diff --git a/drivers/input/serio/serio.c b/drivers/input/serio/serio.c
@@ -694,11 +694,6 @@ EXPORT_SYMBOL(serio_reconnect);
  */
 void __serio_register_port(struct serio *serio, struct module *owner)
 {
-	if (!serio->write) {
-		pr_err("%s: refusing to register %s without write method\n",
-		       __func__, serio->name);
-		return;
-	}
 	serio_init_port(serio);
 	serio_queue_event(serio, owner, SERIO_REGISTER_PORT);
 }

diff --git a/include/linux/serio.h b/include/linux/serio.h
@@ -121,7 +121,10 @@ void serio_unregister_driver(struct serio_driver *drv);
 
 static inline int serio_write(struct serio *serio, unsigned char data)
 {
-	return serio->write(serio, data);
+	if (serio->write)
+		return serio->write(serio, data);
+	else
+		return -1;
 }
 
 static inline void serio_drv_write_wakeup(struct serio *serio)